Hi Bernie --
Pythoneers (or Pythonistas as some say -- snake charmers) do have a
case statement of sorts, thanks to functions (subprocedures) being top
level.
What does that mean?
It means we can pass a function around like a variable, list it, put
it in a dictionary, whatever we can do with most any Python object.
For example:
==== casestructure.py ====
def f():
x = float(raw_input("What number? "))
return x**2 # 2nd powering
def g():
x = float(raw_input("What number? "))
return x**3 # 3rd powering
"""
>>> g()
What number? 10
1000.0
Then:
"""
switch = [None, None, f, g] # a list. Note: switch[2] would be f.
looping = True
while looping:
"""
Show menu, get user input, 0,1 or 2
"""
print """
2. Square a number
3. Cube a number
0. Exit
"""
usersays = raw_input("Choice? ")
if usersays == '0':
looping = False
else:
try:
assert usersays in ['2','3']
usersays = int(usersays)
except:
print "Enter 2,3 or 0"
continue
mychoice = switch[usersays] # in essence, a switch or case statement
output = mychoice() # call whichever function was selected
print output
==== casestructure.py ====
Of course that's not very many choices (just two), but it illustrates
using a list of functions, and a numeric index, to do one of those
loopy menu programs people used to do, pre the dawn of the
event-driven GUI app.
I'm also showing some other charming snake tricks.
Kirby
Cc: edu-sig (where we debate about ways to teach Python to busy
science professionals such as yourself). You may get some follow-up
traffic, we hope on topic.
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